BEA WebLogic Workshop™ Kick Start

Appendix A. Java Essentials

IN THIS APPENDIX

• Your First Java Program

• Declaring Variables

• Operators

• Conversions

• Classes and Objects

• Control Flow

• Exceptions

• Interfaces

• Packages

• Common Java Packages

• Where to Go from Here

Most of the time, when you learn a new language, you start with simple data types—numbers, strings, and so on. Only after you learn how to declare simple variables, and maybe even write a few if/for/while statements, do you venture into the world of objects. If you want to learn Java, however, you need to learn how to create a Java class right away.

Your First Java Program

You can’t write a Java program without creating a class. A class is a grouping of data items and code. A class definition may consist of only code, only data items, or ...